All smog values have deteriorated 1999 Toyota Camry CE manual 205K miles

HC(PPM)

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2011

15mph - meas 55(max 55)

25mph - meas 19(max 39)

2009:

15mph - meas 17(max 55)

25mph - meas 7(max 39)

CO(%)

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2011

15mph - meas 0.22(max 0.50)

25mph - meas 0.12(max 0.48)

2009:

15mph - meas 0.01(max 0.50)

25mph - meas 0.00(max 0.48)

NO(PPM)

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2011

15mph - meas 37(max 437)

25mph - meas 34(max 724)

2009:

15mph - meas 24(max 437)

25mph - meas 20(max 724)

Answer:		Your Toyota's oxygen sensor might be getting a bit "lazy". It seems there's a slight increase in CO emissions as well, indicating a rich mixture. Typically it's the oxygen sensor which is responsible for changes in air/fuel ratio. We'd recommend conducting a propane enrichment test to verify the oxygen sensor's response time and voltage output, and move on from there. If your Toyota is a V6, both oxygen sensors will need to be diagnosed (Bank 1 and Bank 2). posted by SmogTips Support